The present invention relates to a process for purifying an acrylic fiber solvent containing impurities or an aqueous solution thereof. More particularly, the invention is concerned with a process for purifying an acrylic fiber solvent solution which comprises feeding an acrylic fiber solvent containing impurities or an aqueous solution thereof to a packed layer of a polymer consisting of one or more kinds of ester type monomers containing at least one polymerizable double bond and at least one ethylene oxide unit essentially for one molecule or a polymer consisting of such monomer(s) and one or more kinds of monomers containing at least one polymerizable double bond for one molecule, to cause said layer to catch the impurities and fiber solvent, passing an eluent through said packed layer thus eluting the impurities together with the eluent, and passing a further amount of the eluent thereby separating an eluate containing the fiber solvent.